It is proposed to study: (1) properties of adrenodoxin, adrenodoxin reductase, and their complex, (2) purification and properties of cytochrome P450scc and P45011 Beta from bovine adrenocortical mitochondria, (3) substrate availability for cholesterol side chain cleavage reaction of adrenocortical mitochondria, (4) Incorporation of P450scc into artificial phospholipid vesicles. The method of procedure used in this proposal are extensive purification and characterization of enzymes and proteins. By means of reconstitution of these components into a system close to that in the native system of adrenal cortex, we hope to be able to understand the relationship between the steroidogenesis and the action of ACTH.